When an integrated circuit (IC) is formed over a ground plane, there will be portions of the ground plane where electromagnetic (EM) energy scatters from the transitions caused by geometrical discontinuities and impedance mismatches on the IC. This can cause propagation of EM waves between the IC and the ground plane at certain interfering frequencies. If a radio frequency (RF) device is attached to the IC or operating near the IC, the EM waves caused by this EM energy can interfere with the of that RF device, particularly when the interfering frequencies are near the operating frequencies of the RF device.
For this reason, electromagnetic band gap devices have been designed to suppress and control the EM energy that causes the propagation of EM waves between the IC and the ground plane. An electromagnetic band gap device serves to create a band gap in the frequency spectrum of the propagating electromagnetic waves. This frequency band gap is designed to effectively eliminate interference in a desired frequency range by attenuating the potentially interfering signals to such a degree that they are below a threshold of interference. For example, when a radio or a radar device will be operating near the ground plane, the frequency band gap is provided in the operational frequency range of the radio or radar device.
One way of creating such a frequency band gap is through Sievenpiper electromagnetic band gap devices. Such devices resemble an array of tables formed over a ground plane, each of the tables having a single support rod holding it up.